The mergePatchPairs functionality in blockMesh also now uses patchIntersection.

The new mergePatchPairs and patchIntersection replaces the old, fragile and
practically unusable polyTopoChanger::slidingInterface functionality the removal
of which has allowed the deletion of a lot of other ancient and otherwise unused
clutter including polyTopoChanger, polyMeshModifier, polyTopoChange::setAction
and associated addObject/*, modifyObject/* and removeObject/*.  This
rationalisation paves the way for the completion of the update of zone handling
allowing mesh points, faces and cells to exist in multiple zones which is
currently not supported with mesh topology change.

Application
    stitchMesh

Description
    Utility to stitch or conform pairs of patches,
    converting the patch faces either into internal faces
    or conformal faces or another patch.

Usage
    \b stitchMesh (\<list of patch pairs\>)

    E.g. to stitch patches \...

prghUniformTotalPressureFvPatchScalarField: Added p_rgh variant of the time-varying uniform pressure BC

Patch contributed by Stanislau Stasheuski, Aalto University.

meshCheck::checkGeometry,checkTopology: Now cell and face sets are written only if the setWriter is valid

Source-point-to-target-triangle projections might be done in order to
determine the location outside of the target triangle, as well as the
location inside. Forcing the source point inside the target triangle is
therefore only appropriate when constructing the intersection geometry.

This has required switching the order of dependence of the fvMesh
geometry (i.e., Sf, Cf, and C), and the interpolation weights. The
weights are now considered dependent on the geometry fields, and the
geometry fields must therefore construct without reference to the
weights.

Index is a better name to describe a label index than ID which may be an
integer, word or other means of identification.

Indices is a better name to describe label indices than IDs which may be an
integers, words or other means of identification.

This calculation more carefully constructs the direction of the area
stabilisation so as to ensure that it does not oppose the area being
stabilised. This prevents the creation of faces with zero area.

Resolves bug report https://bugs.openfoam.org/view.php?id=4040

solvers::solid::thermophysicalPredictor: Moved thermo correction into the non-orthogonality correction loop

Resolves bug-report https://bugs.openfoam.org/view.php?id=4043

Omega lower limit bounding is now based on a maximum turbulence viscosity nut
rather than a minimum omega value which improves stability and robustness of
the k-omega models in case of numerical boundedness problems.

The maximum nut value is calculated by multiplying the laminar viscosity by
nutMaxCoeff which defaults to 1e5 but can be set by the user in the
momentumTransport dictionary.

Epsilon lower limit bounding is now based on a maximum turbulence viscosity nut
rather than a minimum epsilon value which improves stability and robustness of
the k-epsilon models in case of numerical boundedness problems.

The maximum nut value is calculated by multiplying the laminar viscosity by
nutMaxCoeff which defaults to 1e5 but can be set by the user in the
momentumTransport dictionary.

The boundary condition applied to pressure at open boundaries and outlets is switched
from totalPressure to entrainmentPressure. The latter boundary condition is more robust
since it calculates the pressure for inflow using (velocity) fluxes rather than velocity
on the patch.

Required now that activeBaffleVelocity and activePressureForceBaffleVelocity
have been moved into PDRFoam.

Index is a better name to describe a label index than ID which may be an
integer, word or other means of identification.

Index is a better name to describe a label index than ID which may be an
integer, word or other means of identification.

Index is a better name to describe a label index than ID which may be an
integer, word or other means of identification.

This function has been changed to volume average, making it appropriate
to use on layered meshes in which the cells have non-uniform geometry
within their layers. A 'weightFields' (or 'weightField') control has
also been added, so that mass or phase weighted averages can be
performed within the layers.

Resolves bug report https://bugs.openfoam.org/view.php?id=4041

These conditions are legacy and should not be considered for general
use. They require specific, unintuitive mesh structuring (i.e.,
duplicated boundary faces) that only PDRMesh can now create.

If an an interface is needed which opens or closes based on modelling
criteria, then this should be implemented as an extension of NCC. That
would be more flexible, parallelisable, and would not require
modification of the underlying polyheral mesh.

This simple model generates a phase change between two phases calculated
from the following expression:

    \dot{m}/V = C \alpha \grad \alpha

Where:

    \dot{m}/V | mass transfer rate per unit volume
    C         | coefficient
    \alpha    | volume fraction of the source phase

Example usage:

    coefficientPhaseChange
    {
        type            coefficientPhaseChange;

        phases          (liquid vapour);

        C               [kg/m^2/s] 0.1;
    }

This model may be of use in simple situations, but it is primarily
designed to serve as a prototype for more complex and physical
mechanisms of phase changes.

An enumeration has been added to the arguments of the allocation
coefficient function, eta, to allow specification of how to allocate out
of bounds of the population balance size-groups. There are two options:

- "Clamp" will create an out-of-bounds allocation coefficient of exactly
  one. This partitions unity across all size-space.

- "Extrapolate" will create an out-of-bounds allocation coefficient in
  proportion to the ratio between the given size and the nearest
  size-group size. This does not partition unity outside the range of
  the size-groups.

The previous operation is equivalent to "Extrapolate".

It is not yet clear which method is preferable and under what
circumstances. More testing is required. The enumeration has been
created to facilitate this testing.

as it makes no sense to search for a regular expression which may provide
multiple results and then arbitrarily return the first of them.